The Song sparrow is one of the most abundant, variable, and adaptable native sparrows in North America. Adult birds have brown upperparts with dark streaks on the back and are white underneath with dark streaking and a dark brown spot in the middle of the breast. They have a brown cap and a long brown rounded tail. Their face is gray with a brown streak through each eye.
Song sparrows occur across most of Canada and the United States. Populations of the southern half of their range are non-migratory, but birds from the northern area migrate during winter to the southern United States or Mexico. Song sparrows favor shrubby areas especially near streams and rivers, grasslands, forest edges, fields, beaches, marshes, including salt marshes, and lake edges. They can also be found in gardens and suburban areas.
Song sparrows are generally solitary and highly territorial; during winter and migration, however, they gather in loose flocks. Male use a fairly complex song to declare ownership of their territory and attract females. Singing itself consists of a combination of repeated notes, quickly passing isolated notes, and trills. The songs are very crisp, clear, and precise, making them easily distinguishable by human ears. Song sparrows are active during the day spending most of their time foraging. They feed by walking or hopping on the ground, in shrubs or in very shallow water. They also perform short flights between perches or to cover, pumping their tail downward in flight.
Song sparrows are monogamous and form pairs, however, some birds may exhibit polygynous behavior in which one male mate with several females. They breed from April through August. Males arrive on the breeding grounds earlier than females and establish territories. After the pair was formed the female starts to construct the nest. It is an open cup, made of grasses, stems, leaves, and bark chips, usually lined with fine grasses, rootlets, and hair. Song sparrows nest either in a sheltered location on the ground or in trees or shrubs. The female lay 3 to 5 brown with greenish-white spots eggs per clutch and incubates them for 13-15 days. Chicks hatch helpless, blind, and naked. They leave the nest about 10 days after hatching and become independent from their parents 3 weeks later. At the age of 1 year, young Song sparrows will start to form pairs and breed.
As a whole, Song sparrows are widespread and common throughout their range, however, some populations are threatened by habitat loss, especially in coastal marshes.
According to Partners in Flight resource, the total population size of the Song sparrow is 130,000,000 breeding birds. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.